In recent years, ferromagnetic dielectric (multiferroics) materials, in which a ferromagnetic property and a ferroelectricity coexist and exhibit a multiple action, receive attention and are actively researched and developed.
The ferromagnetic dielectric material is known to exert the following effect: when a magnetic field is applied, a magnetic order of a helical spin type is induced to develop ferroelectricity, and thereby electric polarization occurs, or electric polarization or the dielectric constant changes, and when an electric field is applied, magnetization occurs or magnetization changes, the so-called electromagnetic effect.
Since the ferromagnetic dielectric material can cause a change in magnetization by the electric field and a change in electric polarization by the magnetic field through the above-mentioned electromagnetic effect, various novel and useful ceramic electronic components which use both magnetization and electric polarization, such as inductors, actuators and power generation elements, are expected to be realized.
Patent Document 1 proposes an electromagnetic effect material which is made of an oxide ceramic represented by the general formula (Sr1−αBaα)3(Co1−βBβ)2Fe24O41+δ (wherein B represents one or more elements selected from the group consisting of Ni, Zn, Mn, Mg and Cu, and α, β, and δ satisfy 0≦α≦0.3, 0≦β≦0.3, and −1≦δ≦1, respectively) as a principal component, and has an electromagnetic effect in a temperature range of 250 to 350 K and in a magnetic field range of 0.05 T (tesla) or less.
Patent Document 1 tries to obtain a ferromagnetic dielectric material which has good insulation performance and a desired electromagnetic effect even near room temperature and at a weak magnetic field of 0.05 T or less by using a ferromagnetic dielectric material having a hexagonal Z-type crystal structure represented by the above-mentioned general formula.
Patent Document 1: JP 2012-1396 A (claim 1, paragraph [0010], Tables 1 to 3, etc.)